1. Field of the Invention
This invention relates to thermoplastic aromatic polyether-pyridines and a process for preparing such polymers.
These thermoplastic aromatic polyether-pyridines (hereinafter referred to as PEPs) are thermoplastic resins characterized in that each of their repeating structural units contains one or more pyridine rings and two or more oxygen linkages.
These PEPs have wide applications including molding materials, films, insulating materials for wire coating use, and the like. Moreover, it is expected that electrical conductivity can be imparted thereto by doping the nitrogen atom of the pyridine rings with a metal ion. Furthermore, the PEPs of the present invention are also very useful as functional polymeric materials, because hollow fibers or thin membranes formed of these PEPs have the ability to retain or separate certain cations and are useful as polymeric catalysts for polymer reactions.
2. Description of the Prior Art
No polyether resins composed of repeating structural units each containing a pyridine ring have been known in the prior art.
The present inventors have for the first time developed such unique polyether resins and a process for preparing them.
Conventionally, common aromatic polyether resins have been prepared by condensing an aromatic bisphenol with an aromatic dihalogeno compound. For example, a polyether-ketone resin has been prepared from hydroquinone and 4,4'-difluorobenzophenone (Japanese Patent Laid-Open No. 90296/'79) and a polyether-sulfone resin had been prepared from 4,4'-dihydroxydiphenyl sulfone and 4,4'-dichlorodiphenyl sulfone (Japanese Patent Laid-Open No. 27500/'77).
In these well-known processes, however, the preparation of aromatic polyether resins is possible only when an aromatic dihalide compound whose two halogen atoms are activated by an electron attractive group such as a carbonyl or sulfonyl group located at the para position (e.g., 4,4'-difluorobenzophenone or 4,4'dichlorodiphenyl sulfone) is used as a starting material.
Meanwhile, an attempt has been made to utilize p-difluorobenzene and p-dibromobenzene that have two halogen atoms on the same benzene ring and exhibit relatively high reactivity. However, these compounds do not have sufficient activity to be useful as starting materials for polycondensation reaction, so that no success has been attained in the preparation of resins having a high degree of condensation.
Moreover, condensation polymers derived from para-substituted monomers and hence having a linear molecular configuration, such as the above-described polyether resins, are so rigid that their fluidity is insufficient for molding purposes. In order to obtain better fluidity, there is a need for resins having a nonlinear molecular configuration and, therefore, ones derived from meta-substituted monomers.
Furthermore, with regard to the performance aspect of heat-resistant resins, it is desirable that they have excellent functional properties other than heat resistance. Thus, there is a need for heat-resistant resins which exhibit excellent moldability and other functional properties and/or can be provided with certain electrical properties such as electrical insulating or conductive properties.